I think it'd be fair to say that's a textbook example of "reasonable expectation of privacy". If someone watches you walk down the street, your reaction would

I think it'd be fair to say that's a textbook example of "reasonable expectation of privacy". If someone watches you walk down the street, your reaction would be somewhere on a scale between not even noticing, and thinking they're a busybody. If they joined you in a stall while you expell a few demons, it's a safe assumption you'd rather different opinion of them.